Data Analysis for the E and B EXperiment and Instrumentation Development for Cosmic Microwave Background Polarimetry

The E and B EXperiment (EBEX) was a balloon-borne instrument designed to measure the polarization of the cosmic microwave background (CMB) while simultaneously characterizing Galactic dust emission. The instrument was based on a two-mirror ambient temperature Gregorian-Dragone telescope coupled with cooled refractive optics to a kilo-pixel array of transition edge sensor (TES) bolometeric detectors. To achieve sensitivity to both the CMB signal and Galactic foregrounds, EBEX observed in three signal bands centered on 150, 250, and 410 GHz. Polarimetry was achieved via a stationary wire-grid polarizer and a continuously rotating achromatic half-wave plate (HWP) based on a superconducting magnetic bearing (SMB). EBEX launched from McMurdo station, Antarctica on December 29, 2012 and collected ~ 1.3 TB of data during 11 days of observation. This thesis is presented in two Parts. Part I reviews the data analysis we performed to transform the raw EBEX data into maps of temperature and polarization sky signals, with a particular focus on post-flight pointing reconstruction; time stream cleaning and map making; the generation of model sky maps of the expected signal for each of the three EBEX signal bands; removal of the HWP-synchronous signal from the detector time streams; and our attempts to identify, characterize, and correct for non-linear detector responsivity. In Part II we present recent developments in instrumentation for the next generation of CMB polarimeters. The developments we describe, including advances in lumped-element kinetic inductance detector (LEKID) technology and the development of a hollow-shaft SMB-based motor for use in HWP polarimetry, were motivated in part by the design for a prospective ground-based CMB polarimeter based in Greenland

EXPERIMENTAL STUDY OF THE SCALAR CONCENTRATION FIELD IN TURBULENT FLOWS

An experimental investigation has been carried out in a relatively simple turbulent flow in order to directly measure for the first time the Expected Mass Fraction (EMF) of the state of a contaminant concentration field within a contaminant cloud. Particle image velocimetry (PIV) and Planar laser induced fluorescence (PLIF) were used to measure simultaneous velocity and concentration fields, respectively. The EMF is a relatively simple measure of the state of a contaminant cloud. It has been shown that the EMF is approximately self-similar when concentrations are normalized by the centreline mean concentration. It has been shown that a reasonable approximation of the EMF moments is possible by using the centreline absolute moments. The results are compared with the theoretical and experimental results established for a line source of scalar in grid turbulence. The two closure approximations in the evolution of the moments of the probability density function of a scalar concentration are validated experimentally using simultaneous measurements of velocity and concentration fields. The effect of molecular diffusivity is brought into the convective closure approximation by introducing a representative ‘local concentration scale’, which appears to be a robust improvement in the approximation and can be estimated directly from the centreline moments. The concept o f fractal scaling is used in dealing with under-resolved dissipation measurements by using an extrapolation scheme. This leads to two distinct self-similar regions within the Batchelor scale and the Integral scale, separated by the Kolmogorov scale, in the measured constant of the dissipative closure approximation

Design of a Controller for a Precision Positioning Machine

System identification was used to build an accurate model of a high-precision measurement system. The model built by system identification was compared to modeling by first laws and showed extremely similar results. Pole-placement control design based on the identified system was used to place the systems\u27 dominant poles. The necessary gains to achieve the desired system response were determined by using the identified model and knowledge of the controller structure. The performance of the model-based controller was compared to actual data of the system and showed that control based on the identified model can be used to accurately control the precision measuring machine

Review on Battery State Estimation and Management Solutions for Next-Generation Connected Vehicles

The transport sector is tackling the challenge of reducing vehicle pollutant emissions and carbon footprints by means of a shift to electrified powertrains, i.e., battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs). However, electrified vehicles pose new issues associated with the design and energy management for the efficient use of onboard energy storage systems (ESSs). Thus, strong attention should be devoted to ensuring the safety and efficient operation of the ESSs. In this framework, a dedicated battery management system (BMS) is required to contemporaneously optimize the battery’s state of charge (SoC) and to increase the battery’s lifespan through tight control of its state of health (SoH). Despite the advancements in the modern onboard BMS, more detailed data-driven algorithms for SoC, SoH, and fault diagnosis cannot be implemented due to limited computing capabilities. To overcome such limitations, the conceptualization and/or implementation of BMS in-cloud applications are under investigation. The present study hence aims to produce a new and comprehensive review of the advancements in battery management solutions in terms of functionality, usability, and drawbacks, with specific attention to cloud-based BMS solutions as well as SoC and SoH prediction and estimation. Current gaps and challenges are addressed considering V2X connectivity to fully exploit the latest cloud-based solutions

The Twin-Probe Method: Improving the Accuracy of Langmuir Probes on Small Spacecraft

A Langmuir probe (LP) is a versatile and effective in-situ space plasma instrument for measuring ion and electron densities, and electron temperatures. However, utilizing LPs on very small spacecraft presents challenges that are not experienced on larger, more traditional spacecraft. In particular, a key issue for LP operation on these very small satellites is the negative spacecraft potential induced during LP sweeps due to the limited ion current collection to the spacecraft relative to the electron current collected by the LP. This induced spacecraft charging reduces the accuracy of measurements made by the LP. To mitigate these charging effects, laboratory plasma experiments and computer modeling confirmed that the spacecraft potential can be tracked during LP sweeps using a second, identical probe configured for high impedance potential measurements. By correcting for changes to the spacecraft potential, the LP sweeps can be reconstructed as if they were referenced against a stable potential, providing more accurate measurements of the ambient plasma’s properties. This dual probe measurement is referred to here as the twin-probe method (TPM). This dissertation focuses on the efficacy of the twin-probe method and identifies barriers that must be addressed to maximize its impact. Particle-in-cell simulations were performed using the NASA/Air Force Spacecraft Charging Analyzer Program (NASCAP-2K) to understand which physical processes and system parameters are most critical when analyzing spacecraft charging behavior. A separate MATLAB program called the Plasma-Spacecraft Interaction Codes for Low Earth Orbit (PSIC-LEO) was developed using analytic equations to model spacecraft charging effects on LP current voltage (I-V) curves. Finally, an experiment campaign, performed at NASA Marshall Space Flight Center (MSFC), studied the TPM in a laboratory plasma that approximates a high-density, low-Earth orbit environment. Through these investigations, it was determined that induced spacecraft charging effects result in LP I-V characteristics which overestimate electron temperature and underestimate electron density. Furthermore, regions of the I-V curves have additional non-linear characteristics due to the spacecraft’s induced potential, making traditional Langmuir probe theory more difficult to apply. The TPM is shown to correct I-V curves to provide more accurate estimates of plasma properties. The magnitude of the TPM correction is dependent on the area ratio, defined as the conductive spacecraft surface area divided by the probe surface area. Greater spacecraft charging and, consequently, larger I-V curve corrections when using the TPM, are observed as the area ratio decreases. The method’s largest impact occurs for area ratios below 300. While the TPM is effective for area ratios greater than 300, overlap between measurement uncertainty and the magnitude of correction prevents definitive claims of a maximum area ratio for which twin-probe implementation is necessary. Moreover, since the TPM mitigates the effects of spacecraft charging, but does not mitigate the charging itself, a minimum area ratio of 50 is recommended for this method. Below this area ratio, the TPM can be used, but the spacecraft may charge too negatively to allow the Langmuir probe to reach the plasma potential, reducing the number of useful plasma properties obtained from the incomplete I-V curve. Finally, novel capabilities brought about using a combination of Langmuir probes and other satellite instruments are identified. These capabilities include expanding the measurable range of plasma ion distributions using charged particle energy analyzers and calibrating for environmental effects (like photoelectron current).PHDApplied PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/162984/1/omarleon_1.pd

Misure su motore a magneti permanenti interni a flusso intensificato per un controllo ottimale di coppia

The aim of this final project elaborated is to determine the parameters that characterize the behavior of the IPM-FI motor and to study the reference calculations. Using an algebraic magnetic model it has been possible to use the collected data for the realization of the lookup tables that have been implemented in a Simulink sensorless model in order to realize the simulation to evaluate the correctness of the reference calculations

Modeling, identification, and application of multilayer polypyrrole conducting polymer actuators

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references.Experiments were performed using commercially available, self-contained, multilayer polypyrrole (PPy) actuators to develop low-order lumped parameter models of actuator electrical, mechanical, and electromechanical behavior. Experimental data were processed using system identification techniques. Both grey box and black box models were identified. The grey box model consisted of a first order electrical network that was linearly and algebraically coupled to a second order viscoelastic model. The black box model incorporated a third order Box-Jenkins structure and achieved model to data residues comparable to the grey box model. When utilizing validation data, the grey box model showed very good performance for loads in the range of 0.5 to 3 N. Overall, the results of system identification experiments suggested that low order, lumped parameter models were adequate to describe the gross behavior of multilayer actuators. An online identification scheme was developed for monitoring polymer electrical impedance and thereby monitoring the degradation state of an actuator. This identification was performed successfully using recursive least squares and least squares for a discrete impedance model.(cont.) Experimental validation data, spanning more than 5 hours of continuous operation, were collected and analyzed. A final contribution of this research was the application PPy linear actuators to a custom-designed humanoid foot. Four linear conducting polymer actuators were used to obtain multifunctional behavior of the overall foot. Jacobian analysis of stiffness and damping was performed for the design. Simulations illustrated that PPy actuators through the use of appropriate electrical excitation can modulate their stiffness characteristics as a function of time to match a desired force versus length relationship.by Thomas W. Secord.S.M

An optical distance sensor : tilt robust differential confocal measurement with mm range and nm uncertainty

Compared with conventional high-end optical systems, application of freeform optics offers many advantages. Their widespread use, however, is held back by the lack of a suitable measurement method.The NANOMEFOS project aims at realizing a universal freeform measurement machine to fill that void.The principle of operation of this machine requires a novel sensor for surface distance measurement, the development and realization of which is the objective of the work presented in this thesis. The sensor must enable non-contact, absolute distance measurement of surfaces with reflectivities from 3.5% to 99% over 5 mm range, with 1 nm resolution and a 2s measurement uncertainty of 10 nm for surfaces perpendicular to the measurement direction and 35 nm for surfaces with tilts up to 5°. To meet these requirements, a dual-stage design is proposed: a primary measurement system tracks the surface under test by translating its object lens, while the secondary measurement system measures the displacement of this object lens. After an assessment of various measurement principles through comparison of characteristics inherent to their principle of operation and the possibilities for adaptation, the differential confocal measurement has been selected as the primary measurement method. Interferometry is used as secondary measurement method. To allow for correction of tilt dependent error through calibration, a third measurement system has been added, which measures through which part of the aperture the light returns. An analytical model of the differential confocal measurement principle has been derived to enable optimization. To gain experience with differential confocal measurement, a demonstrator has been built, which has resulted in insights and design rules for prototype development. The models show satisfactory agreement with the experimental results generated using the demonstrator, thus building confidence that the models can be applied as design and optimization tools. Various properties that characterize the performance of a differential confocal measurement system have been identified. Their dependence on the design parameters has been studied through simulations based on the models. The results of this study are applied to optimize the sensor for use in NANOMEFOS. An optical system has been designed in which the interferometer and the differential confocal systems are integrated in a compact design. The optical path of the differential confocal system has been folded using prisms and mirrors so that it can be realized within the allotted volume envelope. For the same reason, many components are adapted from commercially available parts or are custom made. An optomechanical and mechatronic design has been made around the optical system. A custom focusing unit has been designed that comprises a guidance mechanism and actuator to enable tracking of the surface. To achieve a low measurement uncertainty, it aims at accurate motion, high bandwidth and low dissipation. The lateral position of the guidance reproduces within 20 nm and from the frequency response, it is expected that a control bandwidth of at least 800 Hz can be realized. Power dissipation depends on the form of the freeform surface and is a few mW for most expected trajectories. Partly custom electronics are used for signal processing, and to drive the laser and the focusing unit. Control strategies for interferometer nulling, focus locking and surface tracking have been developed, implemented and tested. Various tests have been performed on the system to evaluate the performance. Calibrations must be carried out to achieve the required measurement uncertainty. One calibration is based on a new method to measure tilt dependency of distance sensors. The sensor realized has 5 mm measurement range, -2.5 µm to 1.5 µm tracking range, sub-nanometer resolution, and a small-signal bandwidth of 150 kHz. Using the test results, the 2s measurement uncertainty after calibration is estimated to be 4.2 nm for measurement of rotationally symmetric surfaces, 21 nm for measurement of medium freeform surfaces and 34 nm for measurement of heavily freeform surfaces. To test the performance of the machine with the sensor integrated, measurements of a tilted flat have been carried out. In these measurements, a tilted flat serves as a reference freeform with known surface form. The measurements demonstrate the reduction of tilt dependent error using the new calibration method. A tilt robust, single point distance sensor with millimeter range and nanometer uncertainty has been developed, realized and tested. It is installed in the freeform measurement machine for which it has been developed and is currently used for the measurement of optical surfaces